Story by Jamie Hershman

Photos by Natalie Chan

Multimedia by Isabelle Theilen

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In the back room of Eugene City Bakery, Micah Kenworth sets a heap of dough on a baker’s scale. Ripping a piece from the pale beige blob, he checks the scale again. This time, it aligns perfectly. He begins placing double-fistful mounds of the dough into baskets on a metal cart, repeating the motion until both of the cart’s two shelves are filled with 12 baskets each. It’s almost time for them to be baked into golden loaves of sourdough bread, but before being placed in the oven, the dough must rest and absorb the heat that will activate its yeast. Within minutes the dough is rising, crowning over the baskets’ edges. Lifting the dough to his nose, Kenworth deeply inhales. One sniff, and he knows it’s ready for baking.

Kenworth’s baking process is as much an art as it is a routine. Sourdough bread requires a perfect balance of water, flour, salt, and the most essential ingredients: yeast and bacteria. The principle part of any sourdough bread recipe is the sourdough starter that produces the bread. This simple combination of flour, water, and yeast is much wetter than the average bread dough. Bakers from different regions use a variety of yeasts—whether airborne or those that grow on vegetables or waxy fruits—to generate starters that can last for years. How a starter is conceived is a baker’s secret, but the regional flavor produced by local yeast makes each recipe distinctive. 

Katie McNeil, founder of Pacific Sourdough in Waldport, Oregon, created her starter in 1994 through pure experimentation. After reading an article in Gourmet magazine, McNeil combined a mixture of staple sourdough ingredients with yeast from frozen grapes to create the foundation for her popular bread. She is part of a long line of sourdough bakers that dates back to sixteenth century BCE in ancient Egypt, when a mixture of water and grains used for beer brewing was fermented and led to the discovery of “leavened,” or rising bread.

“I taught myself how to do it,” McNeil says of her starter. She grew up eating her mother’s homemade San Francisco sourdough recipe, but McNeil never learned how to make it, and the starter she uses today is far different from her mother’s. McNeil says she never intended to make a career out of baking, but with the influence of Gourmet’s article and her mother’s tasty sourdough, she fell into the occupation on a whim 20 years ago.

McNeil says the process of making the bread is more complicated than her simple ingredient list suggests. Her 36-hour method includes “feeding” the starter by adding flour and water, fermenting the dough in a large tub, waiting for the dough to rise, and shaping each loaf before placing it in an oven to bake at a high temperature. Despite her lengthy process, McNeil says there’s nothing more satisfying than knowing families across Oregon are making toast with her bread. “I hand-shape every single loaf,” McNeil says proudly.

A simple sourdough starter begins with blending the signature ingredients and leaving them to sit at room temperature. This allows wild yeasts to settle into the mixture and begin the fermentation that produces carbon dioxide gas, a natural leavener. While the carbon dioxide becomes trapped in tiny bubbles that causes the bread to rise, Lactobacillus, a naturally present strain of bacteria, feeds on carbohydrates in the dough and produces the lactic acid that eventually gives the bread its well-known sour flavor. The best sourdough would ideally have a perfect mix of acetic and lactic acid. “You want a balance of those,” McNeil explains, adding that there’s no such thing as a flawless sourdough.

According to Parker Hayes, another sourdough baker at the Eugene City Bakery, a key aspect of baking sourdough, aside from the starter’s consistency, is regulating its temperature—whether it is the room temperature where the starter is stored or an oven’s baking temperature, which McNeil suggests be set at about 450 degrees Fahrenheit. She says warm environments create the hot gas that causes the bread to expand, but they can also influence a sourdough’s flavor by creating more lactic acid in the starter, which produces a less tangy flavor. Colder environments generate more acetic acid, which encourages a sour taste. A starter can be maintained for years by simply feeding the mixture every few days, and sourdough enthusiasts pride themselves on the longevity of their starters because age determines the tanginess of the bread. A starter’s age can also increase the predictability of a sourdough starter.

Since 1849, the Boudin family of the famous San Francisco Boudin Sourdough Bakery & Café has maintained a distinctive starter mixture that is uniquely West Coast. The regional wild yeasts found in the air containing the unique Lactobacillus sanfranciscensis strain of bacteria transformed the family’s sourdough starter into the foundation of their popular bread’s savory tang. The family’s starter, which is still used today, created what has been tradmarked as The Original San Francisco Sourdough. Even if the bread is not made in San Francisco, however, specific acid-tolerant yeasts must be in the air for the bread to take on its famous flavor.

The Eugene City Bakery’s starter originated near San Francisco, in Santa Cruz, California, but over the years it has transformed, enriched by airborne Eugene-area wild yeast. The main difference between baking sourdough versus other breads, Hayes points out, is how long it takes. A simple white or wheat bread might only require about five hours of prep and baking time because it does not rely on yeast to settle into the dough, but sourdough can take as several days just to complete the pre-baking preparation. It’s a lengthy process that requires time and patience to get just the right temperature and humidity combination bakers need to cultivate the perfect amount of yeast.

At Eugene City Bakery, fellow baker Nicolai Otte walks into the back room and immediately picks up one of the sourdough baskets Hayes has set to rest by the oven. Otte examines the bread up close and then pinches the dough delicately as if it were a child’s cheek. A toothy smile spreads over his face. His baker’s sixth sense kicks in, and after a moment of silence he looks up and gushes, “You know when it’s going to be great sourdough.”